# Feature Pack 005: PostgreSQL Database Replacement

> For the complete documentation index, see [llms.txt](https://deploy-preview-472--lucky-concha-f3599f.netlify.app/llms.txt).

![linux/mac support](https://badgen.net/badge/linux%2Fmac/supported/green?icon=linux) ![windows support](https://badgen.net/badge/windows/not%20supported/red?icon=windows)

Status: Implemented Track: `architecture` Previous state: `004-containerized-compose-runtime`

This pack defines an architecture-track branch from `004-containerized-compose-runtime` that replaces the runtime database engine from H2 to PostgreSQL while preserving baseline functional behavior.

Primary intent:

*   replace H2 with PostgreSQL in Docker Compose runtime,
*   keep baseline REST/event contracts stable,
*   keep startup and smoke validation deterministic,
*   keep generation fully spec-first and reproducible.

Core artifacts:

*   `spec.md`
*   `requirements/functional-delta.md`
*   `requirements/nonfunctional-delta.md`
*   `contracts/contract-delta.md`
*   `system/architecture.model.json`
*   `system/runtime-topology.md`
*   `generation/generation-hook.md`
*   `tests/smoke/README.md`

Additional artifacts:

*   `components/postgres-database.md`
*   `conformance/postgres-database.md`
*   `system/docker-compose.postgres.snippet.yaml`
*   `system/postgres-migration-guidance.md`
*   `fidelity-profile.md`

Decision record:

*   ADR: [`docs/adr/006-state-005-use-postgres-for-database-replacement.md`](https://deploy-preview-472--lucky-concha-f3599f.netlify.app/docs/adr/006-state-005-use-postgres-for-database-replacement.md)